net: dsa: hellcreek: Add PTP status LEDs

The switch has two controllable I/Os which are usually connected to LEDs. This
is useful to immediately visually see the PTP status.

These provide two signals:

* is_gm

This LED can be activated if the current device is the grand master in that
PTP domain.

* sync_good

This LED can be activated if the current device is in sync with the network
time.

Expose these via the LED framework to be controlled via user space
e.g. linuxptp.

Signed-off-by: Kurt Kanzenbach <[e-mail]>
Reviewed-by: Andrew Lunn <[e-mail]>
Reviewed-by: Florian Fainelli <[e-mail]>
Signed-off-by: Jakub Kicinski <[e-mail]>

drivers/net/dsa/hirschmann/hellcreek.h

···
 #include <linux/kernel.h>
 #include <linux/mutex.h>
 #include <linux/workqueue.h>
+#include <linux/leds.h>
 #include <linux/platform_data/hirschmann-hellcreek.h>
 #include <linux/ptp_clock_kernel.h>
 #include <linux/timecounter.h>
···
 	struct ptp_clock_info ptp_clock_info;
 	struct hellcreek_port *ports;
 	struct delayed_work overflow_work;
+	struct led_classdev led_is_gm;
+	struct led_classdev led_sync_good;
 	struct mutex reg_lock;	/* Switch IP register lock */
 	struct mutex vlan_lock;	/* VLAN bitmaps lock */
 	struct mutex ptp_lock;	/* PTP IP register lock */
···
 	u8 *vidmbrcfg;		/* vidmbrcfg shadow */
 	u64 seconds;		/* PTP seconds */
 	u64 last_ts;		/* Used for overflow detection */
+	u16 status_out;		/* ptp.status_out shadow */
 	size_t fdb_entries;
 };
 

drivers/net/dsa/hirschmann/hellcreek_ptp.c

···
 			      HELLCREEK_OVERFLOW_PERIOD);
 }
 
+static enum led_brightness hellcreek_get_brightness(struct hellcreek *hellcreek,
+						    int led)
+{
+	return (hellcreek->status_out & led) ? 1 : 0;
+}
+
+static void hellcreek_set_brightness(struct hellcreek *hellcreek, int led,
+				     enum led_brightness b)
+{
+	mutex_lock(&hellcreek->ptp_lock);
+
+	if (b)
+		hellcreek->status_out |= led;
+	else
+		hellcreek->status_out &= ~led;
+
+	hellcreek_ptp_write(hellcreek, hellcreek->status_out, STATUS_OUT);
+
+	mutex_unlock(&hellcreek->ptp_lock);
+}
+
+static void hellcreek_led_sync_good_set(struct led_classdev *ldev,
+					enum led_brightness b)
+{
+	struct hellcreek *hellcreek = led_to_hellcreek(ldev, led_sync_good);
+
+	hellcreek_set_brightness(hellcreek, STATUS_OUT_SYNC_GOOD, b);
+}
+
+static enum led_brightness hellcreek_led_sync_good_get(struct led_classdev *ldev)
+{
+	struct hellcreek *hellcreek = led_to_hellcreek(ldev, led_sync_good);
+
+	return hellcreek_get_brightness(hellcreek, STATUS_OUT_SYNC_GOOD);
+}
+
+static void hellcreek_led_is_gm_set(struct led_classdev *ldev,
+				    enum led_brightness b)
+{
+	struct hellcreek *hellcreek = led_to_hellcreek(ldev, led_is_gm);
+
+	hellcreek_set_brightness(hellcreek, STATUS_OUT_IS_GM, b);
+}
+
+static enum led_brightness hellcreek_led_is_gm_get(struct led_classdev *ldev)
+{
+	struct hellcreek *hellcreek = led_to_hellcreek(ldev, led_is_gm);
+
+	return hellcreek_get_brightness(hellcreek, STATUS_OUT_IS_GM);
+}
+
+/* There two available LEDs internally called sync_good and is_gm. However, the
+ * user might want to use a different label and specify the default state. Take
+ * those properties from device tree.
+ */
+static int hellcreek_led_setup(struct hellcreek *hellcreek)
+{
+	struct device_node *leds, *led = NULL;
+	const char *label, *state;
+	int ret = -EINVAL;
+
+	leds = of_find_node_by_name(hellcreek->dev->of_node, "leds");
+	if (!leds) {
+		dev_err(hellcreek->dev, "No LEDs specified in device tree!\n");
+		return ret;
+	}
+
+	hellcreek->status_out = 0;
+
+	led = of_get_next_available_child(leds, led);
+	if (!led) {
+		dev_err(hellcreek->dev, "First LED not specified!\n");
+		goto out;
+	}
+
+	ret = of_property_read_string(led, "label", &label);
+	hellcreek->led_sync_good.name = ret ? "sync_good" : label;
+
+	ret = of_property_read_string(led, "default-state", &state);
+	if (!ret) {
+		if (!strcmp(state, "on"))
+			hellcreek->led_sync_good.brightness = 1;
+		else if (!strcmp(state, "off"))
+			hellcreek->led_sync_good.brightness = 0;
+		else if (!strcmp(state, "keep"))
+			hellcreek->led_sync_good.brightness =
+				hellcreek_get_brightness(hellcreek,
+							 STATUS_OUT_SYNC_GOOD);
+	}
+
+	hellcreek->led_sync_good.max_brightness = 1;
+	hellcreek->led_sync_good.brightness_set = hellcreek_led_sync_good_set;
+	hellcreek->led_sync_good.brightness_get = hellcreek_led_sync_good_get;
+
+	led = of_get_next_available_child(leds, led);
+	if (!led) {
+		dev_err(hellcreek->dev, "Second LED not specified!\n");
+		ret = -EINVAL;
+		goto out;
+	}
+
+	ret = of_property_read_string(led, "label", &label);
+	hellcreek->led_is_gm.name = ret ? "is_gm" : label;
+
+	ret = of_property_read_string(led, "default-state", &state);
+	if (!ret) {
+		if (!strcmp(state, "on"))
+			hellcreek->led_is_gm.brightness = 1;
+		else if (!strcmp(state, "off"))
+			hellcreek->led_is_gm.brightness = 0;
+		else if (!strcmp(state, "keep"))
+			hellcreek->led_is_gm.brightness =
+				hellcreek_get_brightness(hellcreek,
+							 STATUS_OUT_IS_GM);
+	}
+
+	hellcreek->led_is_gm.max_brightness = 1;
+	hellcreek->led_is_gm.brightness_set = hellcreek_led_is_gm_set;
+	hellcreek->led_is_gm.brightness_get = hellcreek_led_is_gm_get;
+
+	/* Set initial state */
+	if (hellcreek->led_sync_good.brightness == 1)
+		hellcreek_set_brightness(hellcreek, STATUS_OUT_SYNC_GOOD, 1);
+	if (hellcreek->led_is_gm.brightness == 1)
+		hellcreek_set_brightness(hellcreek, STATUS_OUT_IS_GM, 1);
+
+	/* Register both leds */
+	led_classdev_register(hellcreek->dev, &hellcreek->led_sync_good);
+	led_classdev_register(hellcreek->dev, &hellcreek->led_is_gm);
+
+	ret = 0;
+
+out:
+	of_node_put(leds);
+
+	return ret;
+}
+
 int hellcreek_ptp_setup(struct hellcreek *hellcreek)
 {
 	u16 status;
+	int ret;
 
 	/* Set up the overflow work */
 	INIT_DELAYED_WORK(&hellcreek->overflow_work,
···
 	hellcreek_ptp_write(hellcreek, status | PR_CLOCK_STATUS_C_ENA_DRIFT,
 			    PR_CLOCK_STATUS_C);
 
+	/* LED setup */
+	ret = hellcreek_led_setup(hellcreek);
+	if (ret) {
+		if (hellcreek->ptp_clock)
+			ptp_clock_unregister(hellcreek->ptp_clock);
+		return ret;
+	}
+
 	schedule_delayed_work(&hellcreek->overflow_work,
 			      HELLCREEK_OVERFLOW_PERIOD);
 
···
 
 void hellcreek_ptp_free(struct hellcreek *hellcreek)
 {
+	led_classdev_unregister(&hellcreek->led_is_gm);
+	led_classdev_unregister(&hellcreek->led_sync_good);
 	cancel_delayed_work_sync(&hellcreek->overflow_work);
 	if (hellcreek->ptp_clock)
 		ptp_clock_unregister(hellcreek->ptp_clock);

drivers/net/dsa/hirschmann/hellcreek_ptp.h

···
 #define dw_overflow_to_hellcreek(dw)				\
 	container_of(dw, struct hellcreek, overflow_work)
 
+#define led_to_hellcreek(ldev, led)				\
+	container_of(ldev, struct hellcreek, led)
+
 #endif /* _HELLCREEK_PTP_H_ */